Page Settings, scaling "Stave Space" figure cannot be edited in normal ways

On Format/Page Settings, the Scaling of the Stave Space figure is hard to edit or change. The little arrow buttons to raise or lower the size do intelligently alter the size of the Stave Space. They work in the way they used to in Musescore 2. However, I often use this scaling to make the whole score fit better on the pages with no "hanging" bars at the end of the piece, by changing the number (in mm). So I want to change the intelligently suggested figures to my own whilst watching the overall page fit. I could easily change the figures in the Stave Space box in Musescore 2, but cannot do it without problems in Musescore 3.

If you try to edit the number in the box, the format of the field does not allow normal edits. For example, the "Equus, full orchestra" score in your sheet music downloads initially shows a scaling of 1.150 mm on my computers. But if you edit this value, odd things happen. If you backspace out the 5 digit, you cannot replace it with a different digit. Indeed any digit to the right of the decimal point gets replaced with a zero and cannot be changed. This did not happen with Musescore 2! There is something odd about the formatting of this field in Musescore 3.

This little buglet appears on all my scores, both downloaded or created by me.

Derek